Automatic tool control mechanisms



March 27, 1962 Filed June 29, 1959 H. c. FRENTZEL 3,026,834

AUTOMATIC TOOL CONTROL MECHANISMS 5 Sheets-Sheet 1 INVENTOR.

WWQZWM HTTO/PA/[VS March 27, 1962 H. c. FRENTZEL AUTOMATIC TOOL CONTROL MECHANISMS 5 Sheets-Sheet 2 Filed June 29, 1959 March 27, 1962 H. c. FRENTZEL AUTOMATIC TOOL CONTROL MECHANISMS 3 SheetsSheet 3 Filed June 29, 1959 SPOTTING COIL BRAKE COIL RUN COIL TRANSMITTER INVENTOR.

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United fitates Patent 3,026,834 AUTOMATKC TOOL CQNTRUEL MlEtIHANiSMfi Herman C. Frentzel, Milwaukee, Wis, assignor to Hansen Glove Corporation, Milwaukee, Win, a corporation of Wisconsin Filed June 29, 1959, Ser. No. 823,577 4 Claims. (Cl. 112-21?) This invention relates to improvements in automatic tool control mechanisms, and more particularly to a mechanism of the character indicated which includes a two-speed transmitter.

Although the invention is susceptible of wider applications, and is not to be restricted, the present improvements find particular utility in connection with the operation of an electric powered sewing machine which may be operated to apply circuitous seams along the marginal portions of shaped fabric or leather pieces, as for the production of gloves. In this particular field, as well as in others of an analogous nature, in order to maintain proper production requirements, it is desirable for the machine operator to be able to control the sewing machine instantaneously and without undue effort or thought, and to also be able to control the position of the needle or tool with respect to the material being worked on.

By way of example, a sewing machine may be equipped with the improved control mechanism which permits the sewing machine to operate very expeditiously and etficiently on fabric or leather. The sewing machine may be run at high speed, and this is the case when operating along certain portions of the fabric or leather being worked on, but when other portions of the work are reached, in order to permit the operator to turn the fabric and to sew carefully around curved or eccentric marginal portions of the material, it is highly desirable that the machine be susceptible of being stopped quickly and thereafter be operated to produce a slow stitch-by-stitch operation. It is also desirable that the machine be susceptible of operation so as to have the needle stop in the fabric to permit the fabric being pivoted around the down engaged needle, or, there may be a high speed operation, according to the requirements, when the fabric is re-arranged. For some work it is desirable to have the machine operate continuously at a relatively low rate of speed. The control of the sewing machine should be accomplished with a minimum of attention on the part of the operator in order that he may devote his time to the correct feeding and positioning of the work, leaving both hands free for engaging the fabric.

With the present improved mechanism, not only can the machine operator control the machine stitches without removing his hands from the material being worked on, but the improved control mechanism also provides means whereby the operator may automatically position the needle, between sewing operations, so that the material can be properly positioned for the next high speed power sewing. The automatic tool control mechanism of the present invention permits the operator to so operate the machine that the needle or tool can be caused to stop at its up position or at its down position, or the machine may run continuously at a relatively low rate of speed.

In general, the present invention seeks to improve the mechanism described in United States Patent No. 2,692,- 667. The aforementioned patent discusses in detail many of the problems which are involved in the operation of mechanisms of the type under consideration. The automatic tool control mechanism of the present invention is, however, an improvement over that disclosed in the aforementioned Patent No. 2,692,667 in that it is more simple to manufacture, service and operate, and it is far more positive in its action.

In addition to the objectives attained by said Patent No. 2,692,667, the mechanism of the present invention normally operates the machine at a high rate of speed but then steps down to a lower speed before the speed is reduced to Zero. This greatly reduces the impact of the sewing machine on the transmitter mechanism and it permits stopping the machine tool or needle at a more definite predetermined position.

A further object of the invention is to provide an automatic tool control mechanism especially suited for use in connection with a sewing machine and which may be readily built into or associated with a standard electric sewing machine, which is adapted to commercial and large scale operations to maintain high production requirements, which is automatic and flexible in its operation, which is strong and durable, and which is well adapted for the purposes described.

In the accompanying drawings in which the same reference characters indicate the same parts in all of the views:

FIG. 1 is a fragmentary detail sectional view of a sewing machine head wherein the needle reciprocating mechanism has associated therewith and is under the con trol of a centrifugal switch mechanism, shown in section, with the assemblage also including a solenoid actuated clutch and brake electro-transmitter (shown in section) furnishing power to the sewing machine flywheel;

FIG. 2 is a sectional view taken approximately along the line 2-2 of FIG. 1;

FIG. 3 is a sectional view taken on line 33 of FIG. 1;

FIG. 4 is a fragmentary schematic perspective view of the gear mechanism within the electro-transmitter mechanism;

FIG. 5 is a schematic view of the various controls for the mechanism including the wiring diagram; and

FIG. 6 is a schematic view of a modified form of control switch including the wiring diagram therefor.

The present invention, although not restricted thereto, finds particular utility in connection with the operation of a motor driven sewing machine, such as is used in the commercial production of fabric, leather or specific articles especially for the manufacture of gloves or the like.

The machine tool, which in this instance is a recipro eating sewing machine needle, through the improved control mechanism is susceptible of on and 0E operation which can cause the machine tool such as a sewing machine needle to accurately and successively stop at an up or down position, as desired, or the machine, which normally runs at a very high rate of speed, can be quickly brought down and run at a slow rate of speed. Also, before the machine is caused to stop with the needle or tool in a selected position, it will first operate at its low speed, being reduced to said low speed from its normal high speed operation, and then to zero speed. The transition from high speed to slow speed and then to stop or zero speed is in fact almost instantaneous, in actual operation. In a tool equipped mechanism, such as an electric sewing machine, the operator operates the mechanism through unmeditated feather touch on a control pedal and is thereby able to have the machine operate at high speed, at a low speed, or at Zero speed. Additionally, the mechanism can always be stopped with the tool either in its up or down position, which in the case of a sewing machine needle would be out of the work or in the work, according to what is desired.

In the present invention, one unit of the improved control mechanism comprises an electrically controlled solenoid operated transmitter, generally indicated by the numeral and directly associated or incorporated with an electric motor 16. The transmitter 15 and motor 16 are preferably in the form of a unit and carry upwardly directed brackets 17 merging into a horizontal plate 18 whereby the unit may be bolted or otherwise secured to the table portion 19 of a tool equipped mechanism 20, which in the present embodiment is a sewing machine.

The outwardly extending shaft of the electric motor 16 is designated by the numeral 21 and the central hub portion of a flywheel 22 is adjustably secured to a clutch hub 23. A circular member 24 carried fast within the flywheel 22, is provided with a clutch coil 25.

Aligned with the end portion of the motor shaft 21 is an output or pulley shaft 26 whose inner end portion is formed with a spline 27, which spline engages the central hub portion of a disc 28 having clutch and brake facings. When the motor shaft 21 is being driven by the motor 16 and the clutch coil is energized, rotative power is transmitted to the disc 28. Because of the latters splined connection with the inner end of the pulley shaft 26 the output or pulley shaft 26 is directly driven thereby at a high rate of speed. The clutch coil 25 receives its energy through a brush 29 which is connected to a circuit wire (not shown), the other side of the clutch coil 26 being grounded.

There is included in the transmitter a train of gears driven continuously from the motor shaft 21. This train of gears includes the gear 30 which is carried fast by the clutch hub 23, which gear meshes with gear 31, the latter gear being integral with a hub 32 which freely rotates on a jack shaft 33. The numeral 34 designates a stationary energizable spotting coil having a central opening therethrough in which is journaled in suitable bearings the inner end portion of the shaft 33. When the coil 34 is tie-energized, through the force exerted by a coiled spring 35 acting against the hub portion of a splined driving disc 36 the friction face 37 on said drive disc 36 will engage the inner face portion of the gear 31 to thereby cause the disc 36 to be driven which, through the splined connection 38 drives the shaft 33. The outer end portion of the shaft 33 has fast thereon a pinion gear 39 which meshes continuously with an L-shaped gear 40 which is confined between a peripheral face portion of the disc 28 and a fixed hub 41 with an interposed bearing 42. When the clutch coil 25 is energized it draws to the left on the shaft 26 the drive disc 28 and engages the facing 43 thereof. This causes the facing 44 on the disc to be free of driving engagement with the adjacent face of the gear 40. These conditions exist when the output shaft 26 is being directly driven at high speed (approximately 1800 r r.p.m.) by the motor shaft 21 and the train of gears in the transmission will be idling at a reduced gear ratio.

Should it become desirable to stop the operation of the machine 20 and its tool, through the operation of suitable switches, hereinafter to be described, the run clutch coil 25 is de-energized and a brake coil 45 housed within a stationary solenoid core 46, is energized, with the result that the disc 28 becomes disengaged from flywheel 44 and engages the inner face of gear 40- and then disc 28 rotates at the speed of the gear 40. Due to the fact that the disc 28 is keyed to the output shaft 26, the said output shaft and the pulley 47 fast on the outer end thereof, will be driven at the speed of gear 40, which is of substantially reduced speed and in practice, substantially 200 r.p.m. It will be understood, therefore, that prior to completely stopping the machine it is brought down to slow speed.

The tool, which may be a sewing machine needle 48, running at said slow speed, reaches a predetermined selected position with respect to the work it is operating on and when that position is attained, due to the operation of selector switches hereinafter to be described, the coil 34 is energized and that causes the disc 36 on shaft 33 to be drivingly released from gear 31 and to be frictionally brakingly engaged by a portion of a stationary brake face 49. Consequently, rotation of shaft 33 will be stopped, as will rotation of gear 40, whereby rotation of the output shaft 26 and pulley 47 will be terminated.

Referring to FIG. 1 in which the machine tool, by way of example, takes the form of an electric sewing machine, it will be noted that the sewing machine needle 48 is reciprocated by cam members 56 driven by one end portion of the sewing machine shaft 51. The other end portion of the sewing machine shaft 51 carries fast thereon a pulley 52 which is connected with the driving pulley 47 on the transmitter unit by means of an endless belt 53. Fast on the said end portion of the sewing machine shaft 51 is a flywheel 54, which is normally part of the sewing machine, and which has affixed thereto a switch controlling hub 55. There is a radial bore Within the hub 55 in which is reciprocatably mounted a centrifugally actuated plunger 56 which can move centrifugally radially outwardly against the tension of a confined coiled spring 57, the spring being of such strength that centrifugal force of the hub 55 at high speed will be greater than the expansive force of the spring 57. The weighted plunger 56 has afiixed thereto an integral finger 53 which is adapted to reciprocate in a radial bore therefor in the hub which aligns with the bore receiving the plunger 56, and the finger 58 is of such length that when the force of the spring overcomes the centrifugal force against the plunger 56 the outer end of the finger 58 will be projected beyond the surface of the drum 55 to be in position to contact and operate a pair of yieldable switch arms 59 whose inner ends are operatively mounted in the frame portions of conventional switches 66 and 61 which are mounted fast on inner surface portions of a holding frame 62. On the other hand, when the sewing machine shaft 51 is being driven at a high rate of speed the centrifugal force imparted to the Weighted plunger 56 will cause the outer end of the same to overcome the force of the spring 57 and move slightly radially outwardly in its bore to retract the outer end of the operating finger 53 from its projected position so that upon further revolution of the hub 55 the finger 58, being retracted, will not operate the switch arms 59. The respective switches 69 and 6 1, which are shown in their electrical relationship to the other parts of the apparatus in the wiring diagram of FIG. 5, control respectively the needle down and the needle up positions, where the machine under consideration is an electric sewing machine.

Referring to the schematic view and wiring diagram in FIG. 5 it should be observed that the operation of the sewing machine 20 is under the control of an operator who can manipulate with his feet a pair of treadles 63 and 64.. There is also in the circuit a normally closed low speed switch 65 which may be treadle operated. If it is desired to have the machine tool or needle 48 operate at high speed (for instance, 1800 r.p.m.), the operator depresses the treadle 63' which manipulates the switch 63 to the run position shown. Under this condition the current from the source will flow through the circuit wire 66 and energize the run clutch coil 25 in the transmitter 15. The construction and operation of the transmitter was previously described and through the energization of the run coil 25 the output or pulley shaft 26 will be directly driven from the motor shaft 21 at high speed, and through the pulleys and belt 53 the sewing machine shaft 51 will be revolved rapidly or at its high speed to rapidly reciprocate the tool 48 relative to the work.

Supposing a point in the work is reached where the operator desires to stop the operation of the tool or needle and to determine whether the needle is to stop in or out relative to the work. For this purpose the operator releases pressure on the foot treadle 63' which causes the switch 63 to move to the opposite or stop position and simultaneously the operator may operate either of the selector switches 60 or 61 to determine, ac-

cording to his desire, whether the needle is to stop in its down, or in its up position. For instance, if it is determined to stop the machine with the needle in its down position switch 66 is closed by the centrifugal plunger 56 operating within the hub 55 and the operator depresses the treadle 64- so as to have the switch 64 in the position shown in FIG. 5. If the operator chooses to release or raise the treadle 64' then the switch 64 will be in the position reverse to that shown, establishing current flow through the circuit wire 69, and the centrifugal switch actuating means will then operate to stop the needle, through the shaft 51 and earns 56, in its up position through the selector switch 61. When the operators foot releases the treadle 63' and the switch 63 is in the position reverse of that shown for stopping the machine, then current flows through the circuit wire 67 to the brake coil 45 in the transmitter Whose action was previously described. The coil 34 in the transmitter, operation of which is associated with the selector switches 69 and 61, is energized through the circuit wire 68 which connects with the selector switches 65 and 61, as shown. Energization of coil 34 through circuit Wire 68, pursuant to closing either switch 64} or switch 61, will cause disc 36 on shaft 33 to be released from gear 31 and to be quickly braked by engagement with the brake face 49, whereby rotation of shaft 33, gear 40 and output shaft 26 will cease.

There may be situations in which it is desirable to have the machine operated at its low rate of speed, and in this event the procedure above outlined is followed, except that the spotting coil 34 is not energized through either of the selector switches 66 or 61. In this event, through opening switch 65, the clutch coil 25 is deenergized and the brake coil 45 is energized.

From the foregoing description it should be evident that the switch controlling hub 55 associated with a machine such as a sewing machine, which also has incorporated therewith the electrically contiolled solenoid operated transmitter 15, makes it possible, through selected opera; tion of the foot treadle controlled needle up and needle down switches 66 and 61, to have the machine positively stop with the needle in a predetermined up or down position. In reaching this ultimate cessation of operation the machine, however, first slows down from high speed to low speed operation and then to the full stop. By having the operation step down from high speed to low speed the impact on the sewing machine and on the transmitter mechanism is greatly reduced and it also permits attainment of stopping at a very accurately defined spot as, for instance, the up or the down position of the needle or tool. In the stop position it is possible to so operate the machine as to make single stitches by alternately manipulating the microswitch 64. Likewise the machine can be run at its low speed by opening switch 65 when the machine is in its stopped position. Thus, it is possible to perform work which cannot be satisfactorily performed by the tool when it is operating at high speed. In this connection it should be observed that the low speed spotting gearing is already in motion when the stop signal is made. Consequently there is no lapse in time.

In FIG. 6 there is illustrated a modified form of control switch and the wiring arrangement therefor. This modified control switch is in the form of a commutator and includes a disc 75 mounted fast on the outer end portion of the tool shaft 51, in lieu of the hub 55 and its associated mechanism shown in FIG. 1. The major portion of the commutator-like disc '75 is formed of insulating material but it bears on its outer peripheral surface a narrow annular metallic electricity conducting ring 77 having an offset stop pad 78. Adjacent the major portion of the annular ring 77 the insulating surface of the disc 75 is exposed as at 75'. There are a pair of spaced-apart brushes 6t) and 61' whose contacting end portions are aligned with the non-conducting curved surface portion 75 of the disc 75. T 0 one of the brushes, as the brush 66', an end portion of a circuit wire 6? is connected which extends to a terminal on the switch 64. To the other brush 61' there is connected one end portion of a circuit wire 69 which extends to the other terminal of the switch mechanism 64. Positioned to be in continuous electrical contact with the annular metallic ring 77 carried by the disc 75 is a brush 76 to which one end portion of a circuit wire 68 is connected. The other end portion of the circuit wire 68 is connected to the spotting coil 34 in the transmitter mechanism.

As was noted in connection with the principal form of the invention, the transmitter also includes a clutch coil 25 and a brake coil 45. As shown in FIG. 6, the clutch coil 25 is connected by the circuit wire 66 with one terminal controlled by the switch 63. The brake coil 45 is connected by a circuit wire 67 through a shunt wire 79 with the other terminal controlled by the switch 63 and the circuit thereto is closed when the switch 63 is in the position indicated at 63a in FIG. 6. The main extent of the circuit wire 67 extends to the switch 64 but said portion of the circuit can be opened and closed by the switch 65 which, however, is normally closed.

When the foot treadle 63' is manipulated so as to have the switch 63 in the full line position shown in FIG. 6, which is the run position, current will flow through the circuit wire 66 and energize the run clutch coil 25 in the transmitter 15, just as was described in connection with the operation of the principal form of the invention. The output or pulley shaft 26, being driven from the motor shaft 21 at high speed, through the pulleys and belt 53 will cause the tool shaft 51 to be revolved rapidly or at its high rate of speed to rapidly operate the tool. If a point in the work is reached where the operator desires to stop the tool in a predetermined position the operator will release pressure on the foot treadle 63' whereby the switch 63 will assume the broken line position 63a shown in FIG. 6. Then, with the brake coil 45 being energized to rotate the shaft 51 at low speed, and the foot treadle 64' manipulated so that the switch 64 is in the position shown in FIG. 6, the electrical circuit will be established through the circuit wire 69' to the brush 60 with the result that when the commutator disc 75 turns to a point where the stop pad 78 engages the brush 60 the circuit will be closed to the spotting coil 34 which will immediately stop rotation of the output shaft 26 of the transmitter and cause the tool shaft 51 to be stopped at a posi tion which is the predetermined selected position of stoppage of the tool driven by the tool shaft 51. On the other hand, if the foot treadle 64 is manipulated so as to swing the switch 64 away from the full line position shown and into engagement with the other terminal, then there will be a circuit established through the wire 69 to the brush 61', which, when it engages the stop pad 78 of the commutator ring 77, will complete a circuit through the wire 68 to the coil 34, causing the stoppage of the transmitter output shaft 26 and a resultant cessation of rotation of the tool shaft 71 to cause stopping of the tool in a pre determined position different from that established through the brush 6!).

A mechanism such as a power sewing machine equipped with the improved control mechanism can be operated with a ininimum of attention on the part of the operator, leaving his hands free for feeding and positioning the work.

Although the automatic tool control mechanism is especially adapted for causing a tool such as a sewing machine needle to stop or come to rest at a predetermined position with respect to the work, it should be understood that the control mechanism is more generally applicable to various types of movable tools or moving mechanisms which are driven from a rotary shaft, concerning which a selected position of stoppage is desired.

The improved automatic tool control mechanism is furthermore of relatively simple and novel construction, is readily applicable to a standard electric sewing machine or the like, and is well adapted for the purposes set forth.

What is claimed as the invention is:

1. In combination, a tool operating revoluble shaft; a two speed, motor-driven electro-transmitter operatively connected to said shaft to revolve it at high speed or at low speed and to positively stop the shaft at a predetermined position, said transmitter including a run clutch coil, a brake coil and a spotting coil; a first electrical circuit including the run clutch coil; a rotary switch operator carried fast by said revoluble shaft; a second electrical circuit including said spotting coil, said brake coil and said rotary switch operator; a manually operated switch included in and controlling both of said circuits whereby when the first circuit to the run clutch coil is broken the second circuit to the spotting and brake coils will be closed, and vice versa; spaced-apart shaft rest position determining brushes included in said second electrical circuit and in the path of movement of the rotary switch operator to close the second circuit to the spotting" coil through a selected shaft rest position determining brush; a manually operated switch in said second circuit to establish the latter through a preselected shaft rest position determining brush; and a slow speed switch in said second circuit which, when open, breaks the circuit to the spotting" coil, the circuit being maintained through the brake coil to drive the shaft at slow speed.

2. In combination, a tool operating revoluble shaft; a motor-driven electro-transmitter operatively connected to said shaft to revolve it at high speed or at low speed and to positively, instantaneously stop the shaft at a predetermined position, said transmitter including a run clutch coil, a brake coil and a spotting coil; a first electrical circuit including the run clutch coil; a rotary switch operator carried fast by said revoluble shaft; a second electrical circuit including said spotting coil, said brake coil and said rotary switch operator; a main switch included in and controlling both of said circuits whereby when the first circuit to the run clutch coil is broken the second circuit to the spotting and brake coils will be closed, and vice versa; said main switch having a manually operable member normally spring biased to its second circuit closing position but movable under manual pressure to the first circuit closing position; spaced-apart shaft rest position determining brushes included in said second electrical circuit and in the path of movement of the rotary switch operator; a manually operated selector switch in said second circuit to establish the latter through a preselected shaft rest position determining brush to the transmitter spotting coil, said selector switch being selectively operable when the first circuit is closed or opened and becoming immediately effective to stop the shaft through said second circuit at a predetermined position when the manually operable member of the main switch is released so as to move to the second circuit closing position; and a slow speed switch in said second circuit which, when open, breaks the circuit to the spotting coil, said circuit being maintained through the brake coil to drive the shaft at slow speed.

3. In combination, a tool operating revoluble shaft; a two speed, motor-driven electro-transmitter operatively connected to said shaft and having controlled mechanism therein to revolve said shaft at high speed or at low speed and to positively stop the shaft at a predetermined posi-'- tion, said transmitter also including a run clutch coil, a brake coil and a spotting coil; a first electrical circuit including the run clutch coil; a rotary switch operator carried fast by said revoluble shaft; 21 second electrical circuit including said spotting coil, said brake coil and said rotary switch operator; a manually operated main switch included in and controlling both of said circuits and having one position to close the circuit to the run clutch coil and open the second circuit and having a second position to break the first circuit to the run clutch coil and close the second circuit to the spotting and brake coils, spaced-apart shaft rest position determining brushes, included in said second electrical circuit and in the path of movement of the rotary switch operator to close the second circuit to the spotting coil through a selected shaft rest position determining brush; a manually operated switch in said second circuit to establish the latter through a preselected shaft rest position determining brush, and a manually operated slow speed switch in said second circuit which when opened, with the main switch in its second position, opens said second circuit to deenergize the spotting coil while maintaining energization of the brake coil for revolving the tool operating shaft through the slow speed mechanism of the transmitter.

4. The combination with a sewing machine having a vertically reciprocating needle and a driven, revoluble shaft to which said needle is operatively connected, of a motor-driven electro-transrnitter operatively connected to said shaft to revolve it at high speed or at low speed and to positively stop the shaft at a. predetermined position, said transmitter including a run clutch coil, a brake coil and a spotting coil; a first electrical circuit including the run clutch coil; a switch operator carried by said revoluble shaft; a second electrical circuit including said spotting coil, said brake coil and said switch operator; a manually operated switch included in and controlling both of said circuits whereby when the first circuit to the run clutch coil is broken the second circuit to the spotting and brake coils will be closed, and vice versa; spaced-apart shaft rest position determining brushes included in said sec-ond electrical circuit and in the path of movement of the switch operator to close the second circuit to the spotting coil through a selected shaft rest position determining brush; a manually operated switch in said second circuit to establish the latter through a preselected shaft rest position determining brush whereby the sewing machine will quickly stop with the needle in a preselected up or down position; and a slow speed switch in said second circuit which, when open, breaks the circuit to the spotting coil, the circuit being maintained through the brake coil to continuously drive the shaft at slow speed.

References Cited in the file of this patent UNITED STATES PATENTS 1,545,116 Ashworth July 7, 1925 2,517,567 Hill et al Aug. 8, 1950 2,692,667 Bliedung et a] Oct. 26, 1954 2,708,415 White May 17, 1955 2,708,696 Leitner et a1 May 17, 1955 2,747,715 Brinkman et a1. May 29, 1956 2,847,956 Hale Aug. 19, 1958 2,853,967 Schwab Sept. 30, 1958 2,876,407 Winz Mar. 3, 1959 2,942,564- Larys et a1. June 28, 1960 FOREIGN PATENTS 527,908 Germany June 23, 1931 500,729 Italy Nov. 20, 1954 744,660 Great Britain Feb. 8, 1956 750,690 Great Britain June 20, 1956 779,876 Great Britain July 24, 1957 

